1. Field of the Invention
The invention relates to a water filtration system for a refrigerator and more particularly to an indicator for notifying a user when to change the filter.
2. Description of the Related Art
Many refrigerators, and especially those using a side-by-side configuration wherein the fresh food compartment is to the side of the frozen food compartment, include integrated ice and water delivery systems. Typically, such systems deliver water and ice through the door of the frozen food compartment to a ice and water station recessed in the door.
Examples of such systems can be seen in U.S. Pat. No. 5,907,958 issued Jun. 1, 1999 to Coates, et al. and entitled xe2x80x9cRefrigerator water filterxe2x80x9d; U.S. Pat. No. 5,813,245 issued Sep. 29, 1998 to Coates, et al. and entitled xe2x80x9cPressure relief circuit for refrigerator contained water filterxe2x80x9d; U.S. Pat. No. 5,715,699 issued Feb. 10, 1998 to Coates, et al. and entitled xe2x80x9cRefrigerator water filterxe2x80x9d; U.S. Pat. No. 5,707,518 issued Jan. 13, 1998 to Coates, et al. and entitled xe2x80x9cRefrigerator water filterxe2x80x9d; U.S. Pat. No. 5,135,645 issued Aug. 4, 1992 to Sklenak, et al. and entitled xe2x80x9cRefrigerator water filterxe2x80x9d; and U.S. Pat. No. 3,982,406 issued Sep. 28, 1976 to Hanson, et al. and entitled xe2x80x9cRefrigerator water storage and dispensing system with water filterxe2x80x9d.
Increasingly such systems incorporate a filtration system with a replaceable filter element or cartridge so as to improve the quality of the ice and water delivered to the user of the refrigerator. Since the filters must be periodically replaced to maintain the quality of the water, various methods and apparatus could be used to notify the user of the need to change the filter. However, such many potential approaches would be costly, complex and inflexible as to substitution of different types of filters having different useful lives. Furthermore, in an effort to such reduce cost, many such approaches fail to give the user advance warning that the filter will soon need to replaced.
What is needed, therefore, is a filter monitoring and indicating system that is flexible enough to permit its use with different types of filters yet doesn""t add the cost of requiring an additional switch or sensor for detecting the type of filter being used.
What is further needed is an inexpensive filter monitoring and indicating system that not only informs the user that the filter needs to be replaced, but provides earlier warning that the filter will need to be replaced soon and therefore a new filter needs to purchased.
The present invention is directed to a low cost method and apparatus for monitoring the operation of a water and ice delivery system for a refrigerator and indicating when to replace a water filter used in the water and ice delivery system.
The water filter monitoring and indicating method and apparatus of the present invention relies on components existing in many conventional water and ice delivery systems and refrigerators to reduce complexity and number of components and senses the operational condition of the fresh food compartment door and the valves regulating the water flow into the ice maker and the water dispenser of the refrigerator. The method and apparatus monitors and tracks the duration of valve openings to estimate water consumption since the filter has been changed as well as tracking the amount of time that has passed since the last time the filter has been changed. The method and apparatus further tracks user inputs to the fresh food compartment door switch to determine when a filter has been replaced. The water filter monitoring and indicating method and apparatus determines when the filter needs to be changed by comparing the water usage and filter age data with a first set of pre-selected standards for the type of filter being used and further determines when a new filter should be ordered by comparing the water usage and filter age data with a second set of pre-selected standards for the type of filter being used, the second set of pre-selected standards being more stringent than the first set. The method and apparatus then uses a tri-color light emitting diode to display one color when the filter should be replaced, a second color when a filter should be ordered and a third when the filter is good.
In the preferred embodiment of the present invention, the water filter monitoring and indicating system uses a low cost microprocessor to compare the water usage and filter age data with the first and second sets of pre-selected standards, to generate and track a conclusion of a status of xe2x80x9cgoodxe2x80x9d, xe2x80x9corderxe2x80x9d or xe2x80x9cchangexe2x80x9d (or alternatively, xe2x80x9cusedxe2x80x9d) for the filter based on such comparison, and to illuminate the light emitting diode in pre-selected color corresponding to that conclusion of status.
The microprocessor of the water filter monitoring and indicating system of the present invention preferably includes a built-in memory to retain water usage and other data during a power outage.
The light emitting diode of the water filter monitoring and indicating system preferably is illuminated green for a filter status of xe2x80x9cgoodxe2x80x9d, yellow for a filter status of xe2x80x9corderxe2x80x9d and red for a filter status of xe2x80x9cchangexe2x80x9d or xe2x80x9cusedxe2x80x9d.
The water filter monitoring and indicating system preferably further tracks user inputs to the fresh food compartment door switch to determine what type of filter is being used and utilizes a different first and second set of pre-selected standards for each type of filter selectable by the user.
The light emitting diode of the water filter monitoring and indicating system is preferably located within the fresh food compartment of the refrigerator near the fresh food compartment door switch of the refrigerator.
The present invention thereby provides a filter monitoring and indicating system that is flexible enough to permit its use with different types of filters yet doesn""t add the cost of requiring an additional switch or sensor for detecting the type of filter being used by utilizing manual user input to the existing fresh food compartment door switch at a rate which would be unlikely to occur in normal door openings and closings.
What is further needed is an inexpensive filter monitoring and indicating system that informs the user that filter needs to be replaced, by illuminating red and further provides early warning that the filter will need to be replaced soon and therefore a new filter needs to purchased by illuminating yellow.
These and other advantages of the present invention will become apparent to those skilled in the art when the following detailed description of the preferred embodiment is read in conjunction with the accompanying drawings.